A construction machine including an automatic stop function for automatically stopping an engine when predetermined automatic stop conditions (for example, a gate lever for opening and closing a gateway to a cabin is opened and a lever for operating a work actuator is in non-operation) is met has been disclosed in Japanese Patent Laid-Open Nos. 2000-96627 and 2001-41069.
However, when the automatic stop conditions are met, an engine is automatically stopped only by the condition. Thus, when for example an operator leaves a machine for inspections or the like during a warm-up operation after start-up of the engine particularly in the cold time, the engine is automatically stopped in the middle of the warm-up operation.
As a result, the engine is automatically stopped while keeping a low-temperature state in a non warm-up machine, and after that, a restarting operation of the engine puts a heavy load on the engine and peripheral devices such as a water pump and a cell motor (hereinafter referred to as engine and the like), which is likely to cause a failure.
Further, since the restarting operation of the engine must be performed, a heavy load is put on an operator's operation.
It is noted that although only canceling an automatic stop control before warming up the machine is enough to avoid this situation, the operation is troublesome or can be forgotten.
Further, other problems are as follows:    1) since the engine can be suddenly stopped while being in a high temperature state, a heavy load is put on the engine and the like from this point of view;    2) when a period after the engine is stopped by the automatic stop control until restarting the engine is long particularly in the cold time, the engine is cooled down and the restart becomes troublesome. Thus a heavy load is put on the engine and the like even in this case.
It is an object of the present invention to provide an engine control device for a construction machine provided with an automatic stop function, which can protect an engine and the like.